Among the plants most used in folk medicine for the treatment of diabetes are the species of the genus Bauhinia (Fabaceae), popularly known in Brazil as "pata-de-vaca". Of these, Bauhinia forficata has the highest number of studies regarding the hypoglycemic activity. Due to this fact it is included in the Medicinal Plants List of the Brazilian Public Health System. Extracts of pata-de-vaca (B. forficata) have been explored both in relation to its chemical composition and its pharmacological potential. From the chemical point of view the main components identified in hydro alcoholic extract of the leaves are O-glycosylated derivatives of kaempferol and quercetin. Regarding pharmacological properties preclinical studies have confirmed the hypoglycemic effect and antidiabetic of the hydroalcoholic extract of the leaves of B. forficata. The search for evidence of the alleged anti-diabetic activity of B. forficata in clinical level was performed in only two studies, both with few patients, and questionable methodological quality that used tea as a pharmaceutical form, a fact that allows us to question the validity of data considering the risks of no dose reproducibility ingested by patients during the study. Thus the investigators here intend to determine the effects of a standardized extract of B. forficata in the control of patients with diabetes mellitus